Expression of Immune Response Markers in Arab Patients With Lung Cancer

Abstract

PURPOSEProgrammed death-ligand 1 (PD-L1) is a marker for checkpoint inhibitor use in the management of solid tumors, especially in non–small-cell lung cancer (NSCLC). Our study was aimed at determining the patterns of PD-L1 expression and cluster of differentiation 8 (CD8) immunostains in patients with NSCLC in the Arab population.METHODSArchival tumor tissue from patients with a confirmed diagnosis of NSCLC were obtained and stained for PD-L1 with antibody 22C3, using immunohistochemistry staining and giving the tumor proportion score (TPS) as a percentage from 0%-100% of stained tumor cells. Tumors were categorized into negative expressers (TPS 1%): male sex, being Saudi national patients, high expression of CD8+, and presence of tumor-infiltrating lymphocytes. In the multivariate analysis, only high expression of CD8+ cells (≥ 2+) was significant, with an odds ratio of 4.4 (95% CI, 1.5 to 12.9; P = .003)CONCLUSIONPD-L1 expression in our population is similar to the published literature and correlated with the density of CD8+ cells. Validation of the predictive value of this marker in our population and identifying easier and reliable methods to test for it are warranted.